Data storage is a central part of many industries that operate in archival and compliance application environments, such as banks, government facilities/contractors and securities brokerages. In many of these environments, selected data, such as electronic-mail messages, financial documents and/or transaction records are stored for long periods of time. One form of long-term archival storage is storage of data on electronic tape media. Storing data on tape media can be done manually or, with appropriate software, can be done automatically. Storing data on tape media, however, often results in storing redundant or duplicate data, thereby causing inefficient consumption of storage space on the tape media. One of the mechanisms to improve storage consumption is to compress data prior to storing it on the tape. Data may be compressed using, e.g., the LZW compression algorithm, or other suitable compression algorithms. Although using compression algorithms can result in 2:1 space savings, still, data in the compressed form occupies a significant amount of storage space.
Tape media, being a sequential access medium, can be contrasted with a random access medium (such as disks). When data are written to or read from a hard disk drive, the hard disk drive can move its read/write heads to any random part of the disk platters in a very short period of time. In contrast, a tape drive typically spends a considerable amount of time winding the tape to read the requested data. As a result, tape drives typically have slow average seek times (e.g., time to find requested data on a storage medium). Because of the sequential access properties of physical tapes (and thus inherent slow seek time) and their huge capacity, tape libraries are primarily used as the final stage of data archiving.
Therefore, it is desirable to provide a mechanism that improves storage consumption on the storage resources, such as physical tapes.